Arnold Pick described a focal cortical syndrome caused by focal temporal and/or frontal cortical atrophy, later reffered to as Pick's disease (PiD), a prototype of frontotemporal lobar degeneration (FTLD). In contrast to the current concept of PiD, the presence of Pick bodies (tau-positive inclusions) was not thought to be necessary for the diagnosis of PiD. Four out of the seven patients in his original paper had predominant left temporal atrophy and language related symptoms corresponding to semantic dementia. It is now known that most patients with semantic dementia have transactive response DNA-binding protein 43kDa (TDP-43) pathology rather than tau pathology. The original concept of PiD was substantially similar to the current concept of FTLD, which has heterogeneous molecular pathology including tau, TDP-43 and fused in sarcoma (FUS).